accde168 |
1 | /* |
2 | * Watchdog driver for Freescale STMP37XX/STMP378X |
3 | * |
4 | * Author: Vitaly Wool <vital@embeddedalley.com> |
5 | * |
6 | * Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved. |
7 | * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved. |
8 | */ |
9 | #include <linux/init.h> |
10 | #include <linux/kernel.h> |
11 | #include <linux/fs.h> |
12 | #include <linux/miscdevice.h> |
13 | #include <linux/watchdog.h> |
14 | #include <linux/platform_device.h> |
15 | #include <linux/spinlock.h> |
16 | #include <linux/uaccess.h> |
17 | |
18 | #include <mach/platform.h> |
19 | #include <mach/regs-rtc.h> |
20 | |
21 | #define DEFAULT_HEARTBEAT 19 |
22 | #define MAX_HEARTBEAT (0x10000000 >> 6) |
23 | |
24 | /* missing bitmask in headers */ |
25 | #define BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER 0x80000000 |
26 | |
27 | #define WDT_IN_USE 0 |
28 | #define WDT_OK_TO_CLOSE 1 |
29 | |
30 | #define WDOG_COUNTER_RATE 1000 /* 1 kHz clock */ |
31 | |
32 | static DEFINE_SPINLOCK(stmp3xxx_wdt_io_lock); |
33 | static unsigned long wdt_status; |
34 | static const int nowayout = WATCHDOG_NOWAYOUT; |
35 | static int heartbeat = DEFAULT_HEARTBEAT; |
36 | static unsigned long boot_status; |
37 | |
38 | static void wdt_enable(u32 value) |
39 | { |
40 | spin_lock(&stmp3xxx_wdt_io_lock); |
41 | __raw_writel(value, REGS_RTC_BASE + HW_RTC_WATCHDOG); |
42 | stmp3xxx_setl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL); |
43 | stmp3xxx_setl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER, |
44 | REGS_RTC_BASE + HW_RTC_PERSISTENT1); |
45 | spin_unlock(&stmp3xxx_wdt_io_lock); |
46 | } |
47 | |
48 | static void wdt_disable(void) |
49 | { |
50 | spin_lock(&stmp3xxx_wdt_io_lock); |
51 | stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER, |
52 | REGS_RTC_BASE + HW_RTC_PERSISTENT1); |
53 | stmp3xxx_clearl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL); |
54 | spin_unlock(&stmp3xxx_wdt_io_lock); |
55 | } |
56 | |
57 | static void wdt_ping(void) |
58 | { |
59 | wdt_enable(heartbeat * WDOG_COUNTER_RATE); |
60 | } |
61 | |
62 | static int stmp3xxx_wdt_open(struct inode *inode, struct file *file) |
63 | { |
64 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) |
65 | return -EBUSY; |
66 | |
67 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
68 | wdt_ping(); |
69 | |
70 | return nonseekable_open(inode, file); |
71 | } |
72 | |
73 | static ssize_t stmp3xxx_wdt_write(struct file *file, const char __user *data, |
74 | size_t len, loff_t *ppos) |
75 | { |
76 | if (len) { |
77 | if (!nowayout) { |
78 | size_t i; |
79 | |
80 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
81 | |
82 | for (i = 0; i != len; i++) { |
83 | char c; |
84 | |
85 | if (get_user(c, data + i)) |
86 | return -EFAULT; |
87 | if (c == 'V') |
88 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); |
89 | } |
90 | } |
91 | wdt_ping(); |
92 | } |
93 | |
94 | return len; |
95 | } |
96 | |
42747d71 |
97 | static const struct watchdog_info ident = { |
accde168 |
98 | .options = WDIOF_CARDRESET | |
99 | WDIOF_MAGICCLOSE | |
100 | WDIOF_SETTIMEOUT | |
101 | WDIOF_KEEPALIVEPING, |
102 | .identity = "STMP3XXX Watchdog", |
103 | }; |
104 | |
105 | static long stmp3xxx_wdt_ioctl(struct file *file, unsigned int cmd, |
106 | unsigned long arg) |
107 | { |
108 | void __user *argp = (void __user *)arg; |
109 | int __user *p = argp; |
110 | int new_heartbeat, opts; |
111 | int ret = -ENOTTY; |
112 | |
113 | switch (cmd) { |
114 | case WDIOC_GETSUPPORT: |
115 | ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; |
116 | break; |
117 | |
118 | case WDIOC_GETSTATUS: |
119 | ret = put_user(0, p); |
120 | break; |
121 | |
122 | case WDIOC_GETBOOTSTATUS: |
123 | ret = put_user(boot_status, p); |
124 | break; |
125 | |
126 | case WDIOC_SETOPTIONS: |
127 | if (get_user(opts, p)) { |
128 | ret = -EFAULT; |
129 | break; |
130 | } |
131 | if (opts & WDIOS_DISABLECARD) |
132 | wdt_disable(); |
133 | else if (opts & WDIOS_ENABLECARD) |
134 | wdt_ping(); |
135 | else { |
136 | pr_debug("%s: unknown option 0x%x\n", __func__, opts); |
137 | ret = -EINVAL; |
138 | break; |
139 | } |
140 | ret = 0; |
141 | break; |
142 | |
143 | case WDIOC_KEEPALIVE: |
144 | wdt_ping(); |
145 | ret = 0; |
146 | break; |
147 | |
148 | case WDIOC_SETTIMEOUT: |
149 | if (get_user(new_heartbeat, p)) { |
150 | ret = -EFAULT; |
151 | break; |
152 | } |
153 | if (new_heartbeat <= 0 || new_heartbeat > MAX_HEARTBEAT) { |
154 | ret = -EINVAL; |
155 | break; |
156 | } |
157 | |
158 | heartbeat = new_heartbeat; |
159 | wdt_ping(); |
160 | /* Fall through */ |
161 | |
162 | case WDIOC_GETTIMEOUT: |
163 | ret = put_user(heartbeat, p); |
164 | break; |
165 | } |
166 | return ret; |
167 | } |
168 | |
169 | static int stmp3xxx_wdt_release(struct inode *inode, struct file *file) |
170 | { |
171 | int ret = 0; |
172 | |
173 | if (!nowayout) { |
174 | if (!test_bit(WDT_OK_TO_CLOSE, &wdt_status)) { |
175 | wdt_ping(); |
176 | pr_debug("%s: Device closed unexpectdly\n", __func__); |
177 | ret = -EINVAL; |
178 | } else { |
179 | wdt_disable(); |
180 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
181 | } |
182 | } |
183 | clear_bit(WDT_IN_USE, &wdt_status); |
184 | |
185 | return ret; |
186 | } |
187 | |
188 | static const struct file_operations stmp3xxx_wdt_fops = { |
189 | .owner = THIS_MODULE, |
190 | .llseek = no_llseek, |
191 | .write = stmp3xxx_wdt_write, |
192 | .unlocked_ioctl = stmp3xxx_wdt_ioctl, |
193 | .open = stmp3xxx_wdt_open, |
194 | .release = stmp3xxx_wdt_release, |
195 | }; |
196 | |
197 | static struct miscdevice stmp3xxx_wdt_miscdev = { |
198 | .minor = WATCHDOG_MINOR, |
199 | .name = "watchdog", |
200 | .fops = &stmp3xxx_wdt_fops, |
201 | }; |
202 | |
203 | static int __devinit stmp3xxx_wdt_probe(struct platform_device *pdev) |
204 | { |
205 | int ret = 0; |
206 | |
207 | if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT) |
208 | heartbeat = DEFAULT_HEARTBEAT; |
209 | |
210 | boot_status = __raw_readl(REGS_RTC_BASE + HW_RTC_PERSISTENT1) & |
211 | BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER; |
212 | boot_status = !!boot_status; |
213 | stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER, |
214 | REGS_RTC_BASE + HW_RTC_PERSISTENT1); |
215 | wdt_disable(); /* disable for now */ |
216 | |
217 | ret = misc_register(&stmp3xxx_wdt_miscdev); |
218 | if (ret < 0) { |
219 | dev_err(&pdev->dev, "cannot register misc device\n"); |
220 | return ret; |
221 | } |
222 | |
223 | printk(KERN_INFO "stmp3xxx watchdog: initialized, heartbeat %d sec\n", |
224 | heartbeat); |
225 | |
226 | return ret; |
227 | } |
228 | |
229 | static int __devexit stmp3xxx_wdt_remove(struct platform_device *pdev) |
230 | { |
231 | misc_deregister(&stmp3xxx_wdt_miscdev); |
232 | return 0; |
233 | } |
234 | |
235 | #ifdef CONFIG_PM |
236 | static int wdt_suspended; |
237 | static u32 wdt_saved_time; |
238 | |
239 | static int stmp3xxx_wdt_suspend(struct platform_device *pdev, |
240 | pm_message_t state) |
241 | { |
242 | if (__raw_readl(REGS_RTC_BASE + HW_RTC_CTRL) & |
243 | BM_RTC_CTRL_WATCHDOGEN) { |
244 | wdt_suspended = 1; |
245 | wdt_saved_time = __raw_readl(REGS_RTC_BASE + HW_RTC_WATCHDOG); |
246 | wdt_disable(); |
247 | } |
248 | return 0; |
249 | } |
250 | |
251 | static int stmp3xxx_wdt_resume(struct platform_device *pdev) |
252 | { |
253 | if (wdt_suspended) { |
254 | wdt_enable(wdt_saved_time); |
255 | wdt_suspended = 0; |
256 | } |
257 | return 0; |
258 | } |
259 | #else |
260 | #define stmp3xxx_wdt_suspend NULL |
261 | #define stmp3xxx_wdt_resume NULL |
262 | #endif |
263 | |
264 | static struct platform_driver platform_wdt_driver = { |
265 | .driver = { |
266 | .name = "stmp3xxx_wdt", |
267 | }, |
268 | .probe = stmp3xxx_wdt_probe, |
269 | .remove = __devexit_p(stmp3xxx_wdt_remove), |
270 | .suspend = stmp3xxx_wdt_suspend, |
271 | .resume = stmp3xxx_wdt_resume, |
272 | }; |
273 | |
274 | static int __init stmp3xxx_wdt_init(void) |
275 | { |
276 | return platform_driver_register(&platform_wdt_driver); |
277 | } |
278 | |
279 | static void __exit stmp3xxx_wdt_exit(void) |
280 | { |
281 | return platform_driver_unregister(&platform_wdt_driver); |
282 | } |
283 | |
284 | module_init(stmp3xxx_wdt_init); |
285 | module_exit(stmp3xxx_wdt_exit); |
286 | |
287 | MODULE_DESCRIPTION("STMP3XXX Watchdog Driver"); |
288 | MODULE_LICENSE("GPL"); |
289 | |
290 | module_param(heartbeat, int, 0); |
291 | MODULE_PARM_DESC(heartbeat, |
292 | "Watchdog heartbeat period in seconds from 1 to " |
293 | __MODULE_STRING(MAX_HEARTBEAT) ", default " |
294 | __MODULE_STRING(DEFAULT_HEARTBEAT)); |
295 | |
296 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |